Within a steel casting process, for example to produce billets, there is a known need to measure the speed at which the product comes out of casting.
To this purpose, various solutions have been proposed, but they have often proved to be, for various reasons, unsuitable and/or not completely effective.
In particular, methods involving contact are known, for example based on measuring rolls, which are unadvisable given the high temperatures of the products in the casting line, giving rise to problems of slipping, heat dilation and wear which lead to a reduction in the accuracy of the measurements. In particular, the wear on the rolls causes inaccuracies in measuring the speed, just as the presence of sheets of scale determines alterations in the circumference traveled by the rolls and therefore, again, inaccuracies in the measurement.
Doppler effect laser measurers are also known, and therefore without contact, but these are costly and complex and, for low or negative speeds, need expensive acoustic-optical modulators. Doppler effect laser measurers also do not have the possibility of identifying horizontal and vertical movements, due to vibrations of the billet, which makes the measurements of speed unreliable when such vibrations occur.
Furthermore, the presence of sheets of scale or other surface irregularities on the cast product makes measuring with such devices unreliable, and therefore further discourages its use.
Document WO-A-98/53327 describes a method to measure without contact the linear movement of the surface of an object, which provides to calculate the correlation between two images of the moving object taken at successive times.
Document WO-A-2009/008814 describes a device to measure the speed of moving paper, and comprises a light source, an image acquisition element and a control unit that receives the images acquired and, by means of computational means, calculates the speed of the moving paper based on the correlation between the two images acquired.
Document WO-A-2007/085704 describes a method to measure the speed of a surface of a moving object that provides to detect the surface by means of detectors and to construct a response matrix based on the data detected by means of which it determines the speed of the moving surface.
Document U.S. Pat. No. 3,824,015 describes a method and the relative apparatus for the optical measurement of a moving product, such as a rolled metal product, which provides to use two means to detect the luminous energy coming from the product and mounted distanced by a desired distance on a support structure, which detect light signals in a temporally delayed manner one from the others, so as to form an image of the surface of the element of the product on each detection mean, and to generate a corresponding correlation function according to which the value of speed of the product can be calculated.
Purpose of the present invention is to achieve a device to analyze and determine the movement characteristics of oblong products, in particular exiting from a casting line, and to perfect a relative method, which allows, without contact, economically, reliably and accurately, to measure the speed, to detect the movement in the direction of feed or the direction transverse to the direction of feed, to analyze the movements, displacements, vibrations or oscillations, both parallel and orthogonal to the direction of feed of said moving oblong products.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.